The United Nations says it will open a special investigation into an attack in the Democratic Republic of Congo last month that left 15 U.N. peacekeepers dead.

U.N. Secretary-General Antonio Guterres said in a statement Friday that he has appointed Dmitry Titov of Russia, a former U.N. assistant secretary-general, to lead the investigation.

The attack in Congo's North Kivu province on Dec. 7 left 14 Tanzanian peacekeepers and five Congolese soldiers dead. The United Nations said 43 other peacekeepers were wounded in the attack and one remains missing.

The United Nations said Friday the investigation will examine the circumstances surrounding the attack, evaluate the preparedness of the peacekeeping mission in Congo, and provide recommendations to prevent future attacks.

It said the investigation team, which in addition to the officials from the United Nations will also include two military officers from Tanzania, will travel to Congo in early January and will also visit relevant countries in the Great Lakes region.

Following the December attack, a U.N. official told VOA that a Ugandan rebel group known as the Allied Democratic Forces (ADF) is suspected to be behind the violence. The group is an Islamist rebel group that has been active in North Kivu.

The U.N. Security Council said the attack was the worst on U.N. peacekeepers in recent years and said in a statement last month that incident was a reminder of the extraordinary sacrifices made by these brave women and men every day.